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प्रश्न
Write the electronic configuration of K and Ne.
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उत्तर
| Element | Electronic configuration |
| K | 2,8,8,1 |
| Ne | 2,8 |
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संबंधित प्रश्न
The position of eight elements in the Modern Periodic Table is given below where atomic numbers of elements are given in the parenthesis.
| Period No. | ||
| 2 | Li(3) | Be(4) |
| 3 | Na(11) | Mg(12) |
| 4 | K(19) | Ca(20) |
| 5 | Rb(37) | Sr(38) |
(i) Write the electronic configuration of Ca.
(ii) Predict the number of valence electrons in Rb.
(iii) What is the number of shells in Sr?
(iv) Predict whether K is a metal or a non – metal.
(v) Which one of these elements has the largest atom in size?
(vi) Arrange Be, Ca, Mg and Rb in the increasing order of the size of their respective atoms.
Calcium is an element with atomic number 20. Stating reason, answer each of the following questions:-
(i) Is calcium a metal or a non-metal?
(ii) Will its atomic radius be larger or smaller than that of potassium with atomic number 19?
(iii) Write the formula of its oxide.
Name any two elements of group one and write their electronic configurations. What similarity do you observe in their electronic configurations? Write the formula of oxide of any of the aforesaid elements.
Na, Mg and Al are the elements of the same period of Modern Periodic Table having, one, two and three valence electrons respectively. Which of these elements (i) has the largest atomic radius, (ii) is least reactive? Justify your answer stating reason for each case.
The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons in the outermost shell respectively. State the period in which these elements can be placed in the modern periodic table. Write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine.
Write the atomic numbers of two elements 'X' and 'Y' having electronic configuration 2, 8, 2 and 2, 8, 6 respectively.
Which element has a total of three shells, with four electrons in its valence shell?
Use the letters only written in the Periodic Table given below to answer the questions that Follow :
1) State the number of valence electrons in atom J.
2) Which element shown forms ions with a single negative charge?
3)Which metallic element is more reactive than R?
4) Which element has its electrons arranged in four shells?
An element Z has atomic number 16. Answer the following questions on Z:
1) State the period and group to which Z belongs
2) Is Z a metal or a non-metal?
3) State the formula between Z and hydrogen
4) What kind of a compound is this?
Rewrite the following statement after correction, if necessary:
The metallic character of elements in a period increases gradually on moving from left to right.
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the periodic table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?
How does Chemical reactivity of elements change on going from left to right in a period of the periodic table?
Give example in support of your answer.
How does the atomic size vary on going down from top to bottom in a group of the periodic table? Why does it vary this way?
The elements A, B, C, D and E have atomic numbers 9, 11, 17, 12 and 13 respectively. The pair of elements which belongs to the same group of the periodic table is:
(a) A and B
(b) B and D
(c) A and C
(d) D and E
The element which has the maximum number of valence electrons is:
(a) Na
(b) P
(c) Si
(d) A
On moving from left to right in a period of the periodic table, the atomic number of elements increases. What happens to the size of atoms of elements on moving from left to right in a period?
(a) increases
(b) decreases
(c) remain the same
(d) first increases then decreases
What do you understand by periodicity?
What do you understand by orbits?
An element X belong to 4th period and 17th group, state.
name of the element.
Name the element which has the electronic configuration 2, 8, 3?
Which element has:
twice as many electrons in its second shell as in its first shell?
Name the element in period 3 which does not form oxide.
An element 'X' (Atomic number – 20) burns in the presence of oxygen to form a basic oxide.
(a) Identify the element and write its electronic configuration.
(b) State its group number and period number in the Modern Periodic Table.
(c) Write a balanced chemical equation for the reaction when this oxide is dissolved in water.
What is modern periodic law?
Fill in the blank
Most electropositive elements belong to ______ group.
State whether the following statement is true or false
On moving horizontally across a period, number of valence electrons increases from one to eight.
Choose the most appropriate answer from the following list of oxides which fit the description.
An amphoteric oxide: Al2O3 (shows both acidic and basic properties)
Arrange the following as per instruction given in the bracket.
Cs, Na, Li, K, Rb (increasing metallic character)
Arrange the following as per instruction given in the bracket.
Cl, F, Br, I (increasing electron affinity)
Arrange the following as per instruction given in the bracket.
Li, K, Na, H ( decreasing order of their potential ionisation )
Choose the word or phrase from the bracket which correctly complete each of the following statement:
Metals are good ................. (oxidising agents/reducing agents) because they are electron ............. (acceptors/donors).
The elements of one short period of the periodic table are given below in order from left to right:
| Li | Be | B | C | O | F | Ne |
To which period do these elements belong?
The position of elements A, B, C, D and E in the periodic table are shown below:
|
Group 1 |
Group 2 |
Group 17 |
Group 18 |
|
|
|
|
D |
|
|
B |
C |
|
|
A |
|
|
E |
State which is most reactive (i) metal (ii) non-metal
Based on the group valency of element write the molecular formula of the following compound giving justification:
Halide of the elements of group thirteen
State the property trends in general of elements on moving from left to right in a period of the periodic table.
State the property trends in general of elements on moving down in a group of the periodic table.
Name or state following with reference to the element of the first three periods of the periodic table.
The formula of the hydroxide of the element having electronic configuration 2, 8, 2.
Select the correct answer from the options given below.
It is a metal in period 2 having electronic configuration 2, 1?
Complete the table pertaining to the following elements given in Column I.
| Column I Elements | Atomic Number | Electronic Configuration | Underline the element present in that group |
| 1. Hydrogen | 1 | ______ | Be/Na/Ca |
| 2. Carbon | 6 | ______, ______ | N/P/Si |
| 3. Nitrogen | 7 | _______, ______ | C/P/S |
| 4. Oxygen | 8 | _______, ______ | N/S/Cl |
| 5. Sulphur | 16 | _____, ______, _______ | O/N/F |
| 6. Chlorine | 17 | _____, ______, ______ | I/O/S |
